#include <stdio.h>
void RealSwap(double *x, double *y);
int main()
{
    double a, b;
    scanf("%lg %lg", &a, &b);
    printf("%g %g\n", a, b);
    RealSwap(&a,&b);
    printf("%g %g\n", a, b);
    return 0;
}

void RealSwap(double *x, double *y)
{
    double t = *x;
	*x=*y;
	*y=t;
}